title: [Relationship between Runx3 gene expression and its DNA methylation in gastric cancer].
abstract: OBJECTIVE
  This study was designed to clarify the significance of DNA methylation in the expression of runt-related transcription factor 3 (Runx3) gene.
  
  
  METHODS
  Reverse transcription-PCR (RT-PCR) was used to measure the expression level of Runx3 mRNA in paired samples of primary gastric cancer and corresponding non-cancerous gastric mucosa, taken from surgical specimens of 70 gastric cancer patients. Western blot was used to detect the protein expression level of Runx3 gene. The promoter methylation status of Runx3 gene was detected by methylation specific PCR (MSP). Furthermore, RT-PCR was used to mesure the expression of DNA methyltransferase 1 (Dnmtl) mRNA . The correlation of Runx3 expression and methylation with Dnmt1 mRNA expression was analyzed.
  
  
  RESULTS
  The mRNA expression level of Runx3 gene was significantly lower in gastric cancer than that in the matched normal gastric mucosa (0.5740 +/- 0.3580 vs. 1.7250 +/- 0.4080, P < 0.05), and the Runx3 protein expression level in gastric cancer was also significantly lower than that in the matched normal gastric mucosa (P < 0.05). Promoter hypermethylation of Runx3 gene was detected in 50.0% (28/56) of the gastric cancer samples, which resulted in a reduced expression of Runx3 mRNA. It was found that the mRNA expression level of Dnmt1 gene was significantly higher in the gastric cancer tissues with methylated Runx3 gene than that in the ones without. There was a significant correlation of Runx3 gene methylation with increased expression of Dnmtl mRNA (r = 0.64, P < 0.05).
  
  
  CONCLUSIONS
  The promoter hypermethylation may be one of the predominant inactivation mechanisms of the runt-related transcription factor 3 gene, and may be associated with carcinogenesis of human gastric cancer. Reduced Runx3 expression in gastric cancer may be partially correlated with a high level of DNA methyltransferase 1.
authors.affiliation: Department of Gastroenterology, First Hospital of Suzhou University, Suzhou 215006, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Gao
authors.forename: Wei-Chang
authors.initials: WC
authors.lastname: Chen
authors.forename: Jian-Nong
authors.initials: JN
authors.lastname: Cen
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism*; D000328:Adult; D000368:Aged; D050677:Core Binding Factor Alpha 3 Subunit / Q000235:genetics / Q000378:metabolism*; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000096:biosynthesis* / Q000235:genetics; D019175:DNA Methylation; D015536:Down-Regulation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000378:metabolism; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D050677:Core Binding Factor Alpha 3 Subunit; D012333:RNA, Messenger; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human